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Checking auxiliary signals > < Testing modulating piston movement sender and quantity adjuster

A3 Mk1

Diesel Direct Injection and Glow Plug System (TDI 4 cyl.) >07.99
Testing control unit input values
Checking accelerator position sender

The accelerator pedal position sensor is located on the accelerator pedal and conveys driver inputs to the control unit.

  • ‒ Read measured value block, display group 02, engine not running .
 
→ Indicated on display:
Read measured value block 2    ⇒
    0 rpm    0.0 %    0    1    0    18.4 5C
  • ‒ Check display in display zone 2 (accelerator pedal position).
 
→ Specification: 0.0 % (accelerator pedal not depressed)
Read measured value block 2    ⇒
    0 rpm    0.0 %    0    1    0    18.4 5C
  • ‒ Check display in display zone 3.
 
→ Specification:
0 1 0 (accelerator pedal not depressed)
0 0 0 (accelerator pedal depressed)
Read measured value block 2    ⇒
    0 rpm    0.0 %    0    1    0    18.4 5C
  • ‒ Slowly depress accelerator pedal.
 
→ Specification: Display zone 2 must increase steadily up to
100 % (with accelerator depressed).
Read measured value block 2    ⇒
    0 rpm    100.0 %    0    0    0    18.4 5C

On vehicles with an automatic gearbox the kickdown switch pressure point must be distinctly felt before the full throttle stop position is reached.

If the final specified value is not reached:

  • ‒ Adjust accelerator pedal position sender
    => Page 23-18

If the display does not change or only changes irregularly:

  • ‒ Switch ignition off.
  • ‒ Remove connector from injection pump =>Installation position overview, Page 23-3.
 
N23-0018
  • ‒ → Connect multimeter for resistance measurement to the following contacts on the connector:

Accelerator

Contacts

Specified value

Not pressed

1 + 3

0.8...1.4 kω

Not pressed

2 + 3

0.8...1.4 kω

Not pressed

4 + 6

0.8...1.2 kω

Depressed

Indefinite ω

Not pressed

5 + 6
only in vehicles with automatic gearbox

Indefinite ω

fully depressed

0.8...1.2 kω

If specified value is not attained:

  • ‒ Fit a new accelerator position sensor (G79).

If specified value is attained:

  • ‒ Connect test box V.A.G 1598/22 to wiring harness for engine control unit .
 
N23-0017

The following wiring connections are to be checked for open circuits and/or short to positive or negative.

6-pin connector on wiring harness, contact

Test box V.A.G 1598/22, socket

1

24

2

11

3

23

4

12

6

25

Only in vehicles with automatic gearbox:

5

8
  • ‒ Rectify any open/short circuit as necessary.

Checking auxiliary signals > < Testing modulating piston movement sender and quantity adjuster